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View Full Version : Boat Shake/Vibration????


87MCProstar
04-30-2007, 09:48 AM
Took the boat out for the first time this year and seemed to be some noticiable vibration during takeoffand seem to lessen once over 20 mph. I did change to prop, don't know if its possible to put on wrong. But one thing that I have learned is don't assume anything. I have never had a problem like this with a new prop. Felt worse vibrating when one of my old props got dinged up. The rudder, driveshaft and fins on the bottom of the boat seem to be normal. Anyone have any idea where the vibrating is coming from???

east tx skier
04-30-2007, 09:54 AM
As mentioned in the other thread, we/they solved an intermitent vibration on my brother in law's boat by replacing the shaft packing.

mrG
04-30-2007, 10:40 AM
Took the boat out for the first time this year and seemed to be some noticiable vibration during takeoffand seem to lessen once over 20 mph. I did change to prop, don't know if its possible to put on wrong. But one thing that I have learned is don't assume anything. I have never had a problem like this with a new prop. Felt worse vibrating when one of my old props got dinged up. The rudder, driveshaft and fins on the bottom of the boat seem to be normal. Anyone have any idea where the vibrating is coming from???

I had a similar experience on my 92 PS where I had a pronounced vibration at slower speeds. The problem turned out to be one or two of the cylinders not firing (fouled plugs). Once I changed out the plugs the vibration was gone.

Another thought is the strutt bearings. I was told that if they are worn out it will cause vibration in the drive train.

87MCProstar
04-30-2007, 12:14 PM
Okay, well just put new plugs in I'll take them out and check the gap. I thought I gapped 'em right, but just to double check what is the gap supposed to be?

As far as the bearing, how am I able to check to see if thats the problem?

If the problem is just the shaft packing or being and intermitten vibration, is it going to damage the drivetrain while driving until I can find the source? Thanks for the help
Tim

DrJ
04-30-2007, 12:56 PM
This may seem obvious but, if the vibration was not there before you put the new prop on I would try your prop that did not cause vibration. The easiest way to tell if any cylinders are not firing is to feel for warmth after running for a few min. If one if still cool and all others a warm you know if you have a problem child. But you should also notice some power loss. In my experience, when you have vibration on take off it's usually the prop.

87MCProstar
04-30-2007, 02:49 PM
did not feel any power loss during our outing yesterday. as far as the prop after looking at the one I took off (4 blade) one of the blades where knicked twice. the very end of the blade was out of shape, so i have a hard time thinking it was the newly repaired prop, unless there is a way to put it on backwards like a silly fool.

TMCNo1
04-30-2007, 04:07 PM
did not feel any power loss during our outing yesterday. as far as the prop after looking at the one I took off (4 blade) one of the blades where knicked twice. the very end of the blade was out of shape, so i have a hard time thinking it was the newly repaired prop, unless there is a way to put it on backwards like a silly fool.

If it is a tapered shaft, it would be practically impossible to put the prop on backwards.
Is the prop you were running and had the vibration the one you are talking about that you had repaired? I could be, after the repair someone forgot to balance the prop. Who repaired the prop, the original manufacturer or someone local?

east tx skier
04-30-2007, 08:34 PM
I thought I gapped 'em right, but just to double check what is the gap supposed to be?
Tim

Gap should be 0.035

88 PS190
04-30-2007, 09:46 PM
Did you try fitting the prop with prussian blue? to make sure you had good contact?

or is it a splined on your boat?

87MCProstar
04-30-2007, 09:56 PM
TMC,
It is a different prop that I was running, changed from 4 blade back to a 3 blade. The speed difference was to noticable for footin'. I think it is tapered on the H20 side because of the fixed key that is on the shaft, but not sure. The 3 blade was repaired by a third party shop that a marina in the area sends it to, so I would think it would be fully balanced.

88,
Have no clue what prussian blue is. When I put it on as far as it would go by hand, then I used a socket that is big enough to fit over the shaft and to fit on the beefy part of the middle of the prop and used a rubber malet to knock it on far enough to but the lock nut and cotter pin in.

I know that these things are pretty picky and noticed today that I did not get a sticker off completely on the backside of one of the blades. Do you think that has anything to do with it??